1. Field of the Invention
The invention relates to solvents for dissolving cured and/or uncured polyurethane foams.
2. Description of Related Methods
A variety of solvents have been used to clean polyurethane foam from processing equipment, metal parts and tools, both before and after the polyurethane foam has cured on them. Some of the solvents used include such compounds as dimethyl formamide, 1,1,1-trichloroethane, methylene chloride, chlorofluorocarbons, toluene, xylene, acetone, methyl ethyl ketone, ethylene glycol ethers, tetrahydrofuran, and .gamma.-butyrolactone. However, though these compounds are effective solvents, the use of each presents a hazard or complication of one type or another. For example, the chlorine-containing compounds are now thought to contribute to ozone depletion in the atmosphere. The other solvents are either toxic, suspected carcinogens, or very volatile, and thus present health and safety problems.
Applicants have discovered, surprisingly, that polyurethane foam may be dissolved, or removed from a substrate, by contacting the polyurethane foam with a solvent comprising 1,2-dialkyl imidazole. The present inventive process, by substituting in whole or in part 1,2-dialkyl imidazole for the more hazardous prior art solvents, reduces many of the health, safety and environmental hazards associated with the prior art solvents.